NEW YORK CITY— A total of 18 lines, or three-fourths of the subway system, will be affected by changes this weekend, mainly due to construction work aimed at upgrading and maintaining the tracks, the MTA said.

Straphangers who plan on using these lines should allow additional time to travel, officials said.

Here’s the breakdown, line by line

1 LineSouth Ferry-bound 1 trains will run express from 137th Street to 96th Street starting at 11:45 p.m. Friday until 5 a.m. Monday. For service to 125th Street, 116th Street, 110th Street, and 103rd Street, hop on a 1 train to 96th Street and transfer to an uptown 1 train. For service from the skipped stations, take a 1 train to 137th Street or 168th Street and transfer to a downtown 1 train.

South Ferry-bound 1 trains will run express from Van Cortlandt Park-242nd Street to 215th Street from 3:45 a.m. Saturday to 10 p.m. Sunday. For service to 238th Street, 231st Street, and 225th Street, take the Bx9 bus instead. From 238th Street, straphangers can walk or take the Bx9 bus to 242nd Street and then transfer to a South Ferry-bound 1 train.

1 trains will run every 16 minutes between 137th Street and 242nd Street from 8 a.m. to 7 p.m. Saturday and from 11 a.m. to 7 p.m. Sunday. The last stop for some 1 trains heading towards Van Cortlandt Park-242nd Street will be 137th Street. To continue your trip, transfer at 137th Street to a Van Cortlandt Park-242nd Street-bound 1 train.

2 Line2 trains will run local in both directions between 34th Street-Penn Station and Chambers Street from 12:01 a.m. Saturday to 5 a.m. Monday

3 Line3 trains will run local in both directions between 34th Street-Penn Station and Chambers Street from 6:30 a.m. to midnight Saturday and Sunday.

5 Line5 trains will be suspended in both directions between Eastchester-Dyre Avenue and East 180th Street from 11:45 p.m. Friday to 5 a.m. Monday. Free shuttle buses will also operate all weekend between Eastchester-Dyre Avenue and East 180th Street, stopping at Baychester Avenue, Gun Hill Road, Pelham Parkway, and Morris Park. Transfer between trains and shuttle buses at East 180th Street.

5 trains will operate every 20 minutes between East 180th Street and Grand Central-42nd Street days and evenings only.

Bowling Green-bound 5 trains will run local from Grand Central-42nd Street to Brooklyn Bridge-City Hall due to track maintenance at 14th Street-Union Square.

6 Line6 trains will skip Zerega Av and Buhre Av in both directions during spring.

For service to and from Zerega Avenue, straphangers can use the Bx4 or shuttle buses to connect between Zerega Avenue and Castle Hill Avenue. Free transfer will be available with a MetroCard.

For service to and from Buhre Avenue, use the Bx8, Bx24, or shuttle buses to connect between Buhre Avenue and Middletown Road. Free transfer is available with a MetroCard.

7 Line7 trains will be suspended in both directions between Times Square-42nd Street and Hunters Point Avenue from 2:15 a.m. Saturday to 4:30 a.m. Monday. Straphangers can use E, F, N and Q trains for service between Manhattan and Queens. The 42nd Street S shuttle will also operate overnight.

Free shuttle buses will also operate between Vernon Boulevard-Jackson Avenue and Queensboro Plaza, stopping at Hunters Point Avenue, Court Square, and Queens Plaza.

A LineAt all times until Summer 2015, Far Rockaway-Ozone Park-Lefferts Boulevard-bound A trains will skip Rockaway Boulevard. For service to this station take a Far Rockaway-bound A train to Aqueduct-North Conduit Avenue or a Lefferts Boulevard-bound A train to 104th Street and transfer to a Brooklyn-bound A train. For service from this station take a Brooklyn-bound A train to 88th Street and transfer to a Far Rockaway or Lefferts Boulevard-bound A train.

A trains will be suspended in both directions between Ozone Park-Lefferts Boulevard and Rockaway Boulevard from 11:45 p.m. Friday to 5 a.m. Monday. Free shuttle buses will provide alternate service via 80th Street.

Additionally, Howard Beach/Far Rockaway-bound A trains will skip 88th Street. For service to 88th Street, take a A train to 80th Street and transfer to free shuttle buses. For service from 88th Street toward the Rockaways, take a Brooklyn-bound A train to 80th Street and transfer to a Howard Beach/Far Rockaway-bound A.

A service will operate between Inwood-207th Street and Howard Beach/Far. Free shuttle buses will operate between 80th Street and Ozone Park-Lefferts Boulevard, stopping at 88th Street, Rockaway Boulevard, 104th Street, and 111th Street. Transfer between shuttle buses and A trains at 80th street.Inwood-207th Street-bound A trains will run express from Canal Street to 59th Street-Columbus Circle from 11:45 p.m. Friday to 6:30 a.m. Sunday and from 11:45 p.m. Sunday to 5 a.m. Monday.

J LineJ trains will be suspended in both directions between Hewes Street and Chambers Street from 5:30 a.m. to 6 p.m. Saturday and Sunday. 4, 6, and F trains and free shuttle buses will provide alternate service.

J service will operate between Jamaica Center-Parsons Archer and Hewes Street and there will be free shuttle buses providing alternate service between Hewes Street and Essex Street, stopping at Marcy Avenue. Transfer between trains and free shuttle buses at Hewes Street and/or Essex Street.

For direct service between Brooklyn and Manhattan, consider using an A, C or L train via transfer at Broadway Junction.

M LineM trains will be suspended in both directions between Myrtle Avenue and Essex Street from 5:30 a.m. to 6 p.m. Saturday and Sunday. J, L trains and free shuttle buses will provide alternate service.

M service will operate between Metropolitan Avenue and Myrtle Avenue. Use the J for service between Myrtle Avenue and Hewes Street. Free shuttle buses will provide alternate service between Hewes Street and Essex Street, stopping at Marcy Avenue. Transfer between J and M trains at Myrtle Avenue. Transfer between J trains and free shuttle buses at Hewes Street. For direct service to and from Manhattan, straphangers can use a L train via transfer at Myrtle-Wyckoff Avenues.

Q LineQ service will be extended to Astoria-Ditmars Boulevard from 7 a.m. to 9 p.m. Saturday and from 9 a.m. to 7 p.m Sunday. Manhattan-bound Q trains will run express from Kings Highway to Prospect Park from 5:45 a.m. to 8 p.m. Saturday and Sunday.

R LineR trains will be suspended in both directions between 59th Street and 36th Street in Brooklyn from 11:45 p.m. Friday to 6:30 a.m. Sunday, and from 11:45 p.m. Sunday to 5 a.m. Monday.

Manhattan-bound R trains will run express from 36th Street to Atlantic Avenue-Barclays Center from 6:30 a.m. to 11:30 p.m. Saturday and Sunday.

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